Spark plug



Juy 29, 1924u 1,502,768

A. DE CLAIRMONT SPARK PLUG Filed March 29.' 1923 de @La/immobil:

Patent July 29, i924.

asoma oFCE.,

.ADOLFO DE CLAIRMONT, F TOLEDO, GHIIG.`

SPARK PLUG.

To all whom t may concern Be it known that I, ADOLFO DE CLAiRMoN'r,

l citizen of the United States, residing at Toledo, in the county of Lucas and State of Ohio, have invented certain new and useful Improvements in Spark Plugs, of which the following is a specification.

This invention relates to an improved spark plug and seeks, among other objects,

1o to provide a plug wherein the spark points of the plug as well as the plug porcelain may, without removing the plug from an engine cylinder, be effectually cleaned of oil, soot or other foreign deposit.

The invention has as a further object to provide a plug wherein the ignited charge in the engine cylinder may be utilized for burning the deposit from the spark points and porcelain of the plug.

And the invention has as a still further object, to provide a plug wherein the adjustment of the plug to eect cleaning thereof will not molest or disturb the spark gap of the plug.

Other and incidental objects will appear hereinafter. Y

In the drawings:

Figure 1 is a vertical sectional view through my improved spark plug.

Figure 2 is a view similar to Figure 1, showing the bushing of the plug adjusted upwardly.

Figure 3 is a transverse sectional view on the line 3-3 of Figure 2, looking in the direction of the arrows.

Figure 4 is a fragmentary perspective view showing a slight modification of the invention, and

Figure 5 is a fragmentary sectional view showing a further slight modification.

In carryin the invention into eect, I employ a shel which is externally threaded at its lower end to engage in the usual spark plug opening of an engine cylinder and is provided at its upper end with thev fittin the shoulder12 of the shell, effecting a sea ed joint between the bushing and the shell, Furthermore, as will be noted, the bushing is provided at the lower end of the thread thereon with an annular shoulder 16 while the shell is provided with an internal annular shoulder 17 seating the shoulde r 16 to effect a further sealed joint between said bushing and the shell. Formed in the bushing at the lower edge of the shoulder 15 is an annular channel and leading through the wall of the bushing is a plurality of circumferentially spaced radial vent passages 18 opening throughthe bottom wall of said channel. At its lower end portion, below the shoulder 16, the bushing is provided with a reducedcylindrical skirt 19 snugly fitting within the lower` end portion of the shell terminating flush with the lower end thereof, and depending from the lower end edge of the skirt is an electrode 20. Mounted upon the bushing 13 is an insulator 21 of porcelain or other approved material and associated with said insulator are appropriate gaskets 22 forming sealed joints between the insulator and the bushing, the bushing being reamed over at its upper end against the uppermost of said askets firmly binding the insulator in position. As will be noted, the insulator is formed with a tapered lower end portion terminating flush with the lower end of the skirt 19 and eX- tending through the insulator is a center electrode 23 projecting below the lower end edge of the skirt to cooperate withthe electrode 20 forming a spark gap-therebetween. The electrode 23 is permanently fixed upon the insulator and, at its upper end, carries a nut 24 and a second superposed nut 25 for connecting a circuit wire with the electrode.

As will now be seen in view of the foregoing, when the bushing 13 is seated upon the shell 10, the lug will function in the manner of an ordinary spark plug. However, should the electrodes 20 and 23 become fouled at the spark gap therebetween, the bushing may, without removing the plug from an engine cylinder, be counter-rotated upon the shell 10 and thus adjusted upwardly until, as shown in Figure 2, the passages 18 clear the upper end of the shell. When a circuit is then closed through the lu a charge in the engine cylinder will ge red by the plug with the result that the ignited charge will rise upwardly over the electrode 20 and the lower end of the electrode 23 as well as around the lower end portion of the insulator 21 to discharge to theair through said passages. As will be appreciated, the ignited charge will, of course, `be under compression so that the flame produced will be caused to forcrbly strike the electrodes as well as also forcibly strike the lower end portion of the insulator for effectually and quickly burning any foreign deposits therefrom and, in th1s connection,- particular attention' is directed to the fact that when the bushing is adjusted upwardly upon the shell, the gap between the electrodes is not molested or varied in any way. Proper functioning of the plug, 1n the elevated position of the bushing, is accordingly insured, while trouble with the plug such as might be caused through a relative shifting ozt' the electrodes is also prevented. Having cleaned the plug, the bushing 13 is .again screwed downwardly upon the shell 10 for closing the passages 18 and sealing the connection between the bushing and the shell, a closed joint 'being provided below said passages by the shoulders 16 and 17 and above said passages by the beveled shoulders 12 and 15. Leakage of compression through the plug will thus be effectu- `ally overcome.

In Figure 4 of the drawings, I have illustrated a slight modification of the invention. In this modification, the skirt of-the bushing of the plug is indicated at 26 and formed on the skirt at its lower end edge are tongues tapered toward their tree ends and bent inwardly at right angles to define electrodes 27 approaching the center electrode of the plug at their free ends to define spark gaps between said electrode and the electrodes of the bushing. Otherwise, this modification is identical with the preferred construction.l

In Figure 5 of the drawings, 'I have illustrated a further slight modification wherein the bushing of the plug is indicated at 28 and the insulator thereof at 29. In this modification, the insulator is removably secured upon the bushing by a nut 30 threaded into the bushing so that should it become necessary, the insulator may be readily removed. Otherwise, this modification is identical with the preferred embodiment and further description is accordingly believed unnecessary.

Having thus described the invention, what iselaimed as new is:

1. A spark plug including a shell, a bushing thereon having a vent passage through its wall normally covered by the shell, the bushing being provided with a depending skirt slidably fitting Within the lower end portion of the shell for centering and guiding the bushing, an electrode carried by said skirt, and an electrode insulatingly supported by said bushing to cooperate with said first mentioned electrode forming a spark gap therebetween, the bushing being adjustable upon the shell to uncover said .passage without disturbing the gap.

2. A spark plug including a shell provided at its upper end with a beveled seat, a bushing threaded upon the shell snugly fitting therethrough and provided at its upper end with a head having a beveled shoulder fitting said seat forming a closed joint between the shell and bushing, the bushing being provided at the lower edge of said shoulder with an annular channel and being formed with a vent passage through its wall opening through the bottom wall of said channel, an electrode upon' the bushing, and an electrode insulatingly supported by the bushing to cooperate with said first mentioned electrode forming a spark gap therebetween, the bushing being adjustable upon the shell for uncovering said passage.

3. In a spark plug, the combination of a shell, a bushing screwed into the shell and having a vent passage normally covered by the shell, an internal shoulder on the shell, an external shoulder on the bushing at a point between the ends thereof seating against said first named shoulder forming a sealed Vjoint between the shell and bushing in a plane below said passage, an insulator carried by the bushing, an electrode carried by the insulator, an electrode upon the bushing to cooperate with said first named electrode forming a spark gap therebetween, the shell being counterbored at its upper end to iorm a seat, and a shoulder upon the bushing fitting said seat to form a sealed joint between the. shell and bushing in a plane above said passage, the bushing being adjustable upon the shell to uncover said passage without disturbing the length of said gap.

In testimony whereof I afiix my signature.

ADOLFO de CLAIRMONT, Md. [L. s.] 

